Introduction: special issue commemorating the 155th anniversary of Geological Magazine

© Cambridge University Press 2020. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction: special issue commemorating the 155th anniversary of Geological Magazine

This brief historical account of the the journal's leadership since its foundation in 1864 highlights the dominance of British, and especially Cambridge, scientists in Geological Magazine's core editorial team throughout the 20th century. As of recent times, it also includes colleagues from overseas.
The first issue (July 1864) of the journal begins with a four-page introductory section entitled 'The past and present aspects of geology'. Its first paragraph reads, 'The publication of the First Number of a new Journal of Geology seems a fit opportunity for noticing the present aspects of the Science, as compared with those it presented during the few principal epochs into which the short term of its existence may be divided; and also for contrasting the ideas that during each of those epochs guided the course of geological investigation, forming for the time, so to speak, the rudder of geological thought' (Anonymous, 1864). The section ends with the following statement, which is still be regarded as valid today: 'Finally, by favouring no one school or theory more than another, criticizing fearlessly and uncompromisingly where it appears necessary, though laudatory where it is desirable, we hope to establish for the GEOLOGICAL MAGAZINE that independent character which will alone cause it to be regarded as an impartial tribunal, whose verdict will command respect by reason of its justice' (Anonymous, 1864).
The first original article published in Geological Magazine was by John William Salter (1820-1869), an English geologist and palaeontologist who had worked for the Geological Survey, and is entitled 'On some points in ancient physical geography, illustrated by fossils from a pebble-bed at Budleigh Salterton, Devonshire'. Therein, Salter (1864) reports on Palaeozoic fossils, chiefly of trilobites, large bivalve shells and brachiopods from Budleigh Salterton in East Devon. Since the journal's foundation, a large number of original articles, editorial notes, book reviews, correspondences and obituaries, among others, have been published in Geological Magazine. The three most widely cited papers published in Geological Magazine before 1950 were by Spath (1926), Lapworth (1873), and Richthofen (1882). The three most widely cited since 1950 are by Bott (1959), Harley (1989) and Marshall (1992).
Originally, the journal was printed by the publishing company Longman & Co. in London. The journal has changed publishing company a few times, and since 1970 has been published by Cambridge University Press. Since January 1986 the journal has offered a student subscription rate and the opportunity to publish colour plates. A limited number of free colour plates each year were made available to authors; the editors decided which plates to accept on their scientific merit (Anonymous, 1985).
Today, many publishers face challenges in maintaining high standards while keeping publication costs at a reasonable level. The push toward Open Access publishing, making the research outputs freely available online, is another challenge. The request that authors pay for some or all of the publication costs seems to have been ongoing for a long time. The following Geological Magazine editorial notes from January 1921 bring to light the financial struggle being faced by the editors about 100 years ago: 'They still, however, find themselves faced with financial difficulties of a serious nature, arising from the continued increase in the cost of production. For the first half of 1920 a small profit was made, but this was almost wiped out by a considerable further rise in the cost of printing in the middle of the year. An important item in expenses is the cost of plates, and they are regretfully compelled to inform their contributors that it will under present conditions be impossible to produce plates at the expense of the Magazine. They feel sure, however, that their friends will not hesitate to incur the expense involved in meeting the cost of the illustrations, which are so necessary to bring out the full value of their papers. Many of them have done so voluntarily in the past, and the Editors trust that even under the present conditions, that bear so heavily on people of moderate means, they will be able to continue to provide them ... we should 2 G Meinhold like also to take our readers and subscribers into our confidence and to inform them that although arrangements have been made which, at any rate, ensure continuance for 1921, there are limits to this sort of thing. In the first place it should be made quite clear that the Editors receive no remuneration, and arc, as a matter of fact, slightly out of pocket as the result of their labours. Nevertheless, they do their work gladly in the interests of geological science, which they earnestly hope is really benefited by the continued existence of the Magazine, and they would feel the greatest regret if they were compelled by force of circumstances to relinquish their self-imposed labour of love' (Anonymous, 1921). With these insightful editorial notes in mind and the brief historical account of the journal's early days onward, we now move on to the collection of papers in this special issue of Geological Magazine highlighting various topics of the earth sciences to commemorate the 155th anniversary of the journal's publication.
The diversification of complex life during the early Palaeozoic, when all modern marine phyla first appeared, is a research topic of great interest. Harper et al. provide a review of biodiversity curves of the marine organism for the Cambrian-Silurian and show that a single, long-term, background radiation of life took place during that time interval, including both the 'Cambrian Explosion' and the 'Great Ordovician Biodiversification Event'. Different regional radiations, however, at smaller scales, can be recognized geographically. The availability of more complete datasets, with better global coverage, and more advanced analytical techniques, will allow further insights into studies of biodiversity through time.
Grazhdankin et al. discuss the Tommotian Regional Stage of the Siberian Platform that has been closely linked to the idea of the 'Cambrian Explosion'. They use a multidisciplinary approach, including biostratigraphy, carbonate δ 13 C values and U-Pb zircon dates, among others, to study an informal 'synstratotype' of the lower Tommotian boundary in the upper Mattaia Formation, Kessyusa Group in the Olenek Uplift, NE of the Siberian Platform. A section of the upper Mattaia Formation is suggested here as a model for the Global Boundary Stratotype Section and Point (GSSP) for the base of the Cambrian Stage 2.
During the early Cambrian, the first trilobites appear in the fossil record. They are a group of extinct marine arthropods that lived throughout the majority of the Palaeozoic Era. Paterson briefly reviews the complex history of trilobite classification over the last century, including a discussion on the phylogenetic links between major post-Cambrian trilobite clades and their Cambrian sister taxa. He also highlights some of the perpetual problems that impair the systematics of this invertebrate group, and outlines future directions for research on trilobite systematics.
Another research topic of great interest is the colonization of land by living organisms, as this profoundly affected Earth's biosphere, geosphere and atmosphere. The Devonian Rhynie chert Konservat-Lagerstätte located in Aberdeenshire, Scotland, is well known for its terrestrial fossil record, preserving an important early terrestrial ecosystem, including plant, fungal, bacterial and arthropod fossils. Garwood et al. review the geological setting of the Rhynie Basin, the palaeoenvironment at the time of deposition of the cherts which host the famous fossils, and the taphonomy of the fossils themselves. Without any doubt, the Rhynie ecosystem provides unique insights into early life on land.
On several occasions in Earth's history, life has been challenged by mass extinction events. The largest and therefore arguably the most important is the Permian-Triassic boundary extinction event which killed off more than 95 % of the marine and 70 % of the terrestrial species on Earth. Studying stratigraphic sections across the Permian-Triassic boundary is therefore important for better understanding the precise timing of this and other events. Ellwood et al. show that the expanded Permian-Triassic boundary succession at Lung Cam in Vietnam is a high-resolution proxy which can be well correlated to the Permian-Triassic boundary GSSP located at the Meishan D section in China and can be effectively used to correlate to successions where the GSSP-defining fossils and related biostratigraphy are not well defined or are missing.
Another important boundary succession covers the time interval from the Eocene to the Oligocene, which coincides with the main climatic shift from relatively warm to relatively cold conditions in the Cenozoic Era and represents a greenhouse to icehouse transition. Well-constrained regional to global high-resolution correlation and timing is essential for better understanding such transition. Ellwood et al. use a multi-proxy approach, including a combination of lithostratigraphic, magnetostratigraphic (magnetic susceptibility), geochemical and biostratigraphic methods, to unravel various changes across the Eocene-Oligocene transition in five successions located in the SE United States Gulf Coastal Plain and to correlate those to the GSSP in the Massignano section located near Ancona in central Italy. For example, magnetic susceptibility data reflect relatively well-defined, low-magnitude climate cycles during a time of slight climate warming in the uppermost Eocene, whereas relatively large-magnitude cycles occur in the lowest Oligocene as climate slowly begins to cool.
The final contribution in this special issue focuses on metamorphic core complexes. Searle & Lamont discuss the evolution of the metamorphic core and how rocks that formed at lower crustal depths were uplifted to high structural levels. Also, low-angle ductile shear zones and normal faults that bound the upper level of metamorphic core complexes are addressed. The observed extensional fabrics in compressional orogenic settings challenge the widely accepted definition of metamorphic core complexes. The authors suggest that compressional core complexes are as common as extensional core complexes, and many core complexes previously attributed to lithospheric extension and isostatically driven uplift may need to be re-examined.
As shown in this special issue and previous issues, Geological Magazine publishes original scientific papers covering the complete spectrum of earth sciences topics, with high-quality illustrations. Its worldwide circulation and high production values, combined with Rapid Communications and Book Review sections, keep the journal at the forefront of the field. All of this is only possible with the help and support of the editors and referees, and the publishing staff at Cambridge University Press, who ensure that the high publication standards of the journal are maintained. Many thanks are also due to the authors who have contributed to publications in Geological Magazine to date.